This invention relates to an improved bicycle seat post for connecting a saddle to a bicycle frame so that the saddle will be held firmly.
The seat post of this invention enables angular adjustment of the saddle fore and aft for optimum positioning of the saddle. It also enables forward and rearward adjustment of the saddle.
Seat posts are almost universally used for the general purpose of securing saddles to bicycle frames. It is generally recognized that such seat posts should permit some adjustment of the seat position of the saddle, for small variations in saddle position can greatly affect the over-all comfort and efficiency of the rider. It is also important that a seat post bought separately from the bicycle be suitable for use with a large number of the many types of bicycle frames that are in use and with most or all of the many types of saddles that are in use.
Heretofore, seat posts have relied for adjustability on two bolts used to secure them to a pair of saddle rails, the tension of one bolt opposing the tension of the other. Angular adjustment has had to be provided by tightening one bolt and loosening the other. However, such systems have been unsatisfactory for a number of reasons:
1. Normal riding loads cause cyclic stretching and contracting of the bolts within their elastic limits, and this cyclic action has frequently resulted ultimately in fatigue failure of the bolts, which tend to crack or break. Structure of this type is generally avoided in aircraft engineering and other fields where high reliability is sought, but not in bicycles. The present invention seeks to overcome this significant problem.
2. Seat posts in use prior to this invention have been very difficult to adjust for obtaining the proper angular position of the saddle. One reason for this difficulty is that the two bolts used in clamping the post to the saddle rails had to be skillfully tightened and loosened relative to each other and in proper opposition to each other in order to obtain the correct angle and the correct final bolt tension, both of which are necessary. The skill was difficult to acquire and difficult to teach to others.
3. Prior-art seat posts have generally located the bolt heads up under the saddle, and this location has made access difficult; so it has been hard to apply a wrench to them and to turn them with proper control.
4. Seat posts prior to this invention have been relatively complex mechanically, and the component parts have been relatively expensive to manufacture.
5. Prior-art seat posts have been unduly heavy. They have been made from heavy metals, partly because their use of two bolts in opposition causes undue strain and is unduly fatiguing even for heavy metals. The weight of these seat posts has thus added significantly to the weight of bicycles which, otherwise have been made quite light in weight, to help the cyclist obtain additional speed, additional endurance, and climb more easily, since the cyclists legs must carry the weight of the bicycle over hills whether or not there are gear-change arrangements.
Thus, among the objects of the invention are: to provide a bicycle seat post which is less liable to suffer breakage or cracking due to metal fatigue; to provide a bicycle seat post which is much easier to adjust for obtaining proper saddle position than has been true in the past; to provide an inherently light bicycle seat post; to provide an inherently strong and durable seat post; to provide a seat post which is relatively inexpensive to manufacture; to provide a simpler seat post with relatively few parts; and to obtain a generally improved seat post which is easier to manufacture, less expensive, and gives superior performance and results in superior comfort to the rider.